Buildup factors BNfor the number of gamma-rays in C, H2O, Al, Cu and Pb absorbers have been measured and the variation of BNwith the atomic number Z and the thickness of the absorber were investigated. Linear absorption coefficient and the buildup factor of a soil sample were measured and the effective-Z (Zeff) of the sample was estimated from BNversus Z curve. The soil sample was also analyzed for its constituents to evaluate its absorption coefficient and the Zeffwas re-determined. The results obtained using these two methods were compared and they were found to be in good agreement.